Karim Belabas on Sat, 01 Jan 2022 16:36:28 +0100


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Re: Error in qfauto() && Happy New Year


* Georgi Guninski [2022-01-01 10:56]:
> M1=[1, 0, 0, 0, 0, 1, 0, 1, 0, 1; 0, 1, 1, 0, 1, 0, 0, 0, 1, 0; 0, 1,
> 1, 0, 0, 0, 1, 1, 0, 0; 0, 0, 0, 1, 1, 1, 0, 0, 0, 1; 0, 1, 0, 1, 1,
> 0, 1, 0, 0, 0; 1, 0, 0, 1, 0, 1, 0, 1, 0, 0; 0, 0, 1, 0, 1, 0, 1, 0,
> 1, 0; 1, 0, 1, 0, 0, 1, 0, 1, 0, 0; 0, 1, 0, 0, 0, 0, 1, 0, 1, 1; 1,
> 0, 0, 1, 0, 0, 0, 0, 1, 1]
> qfauto(M1,M1)
> *** impossible inverse in divrr: 0.E-19.

Bad Input Bug: M1 must be a positive definite quadratic form, but

(16:33) gp > qfsign(M1)
%1 = [7, 3]

qfauto(M1) also fails. The error actually occurs in qflllgram(M1)
(BIB: M1 is not a Gram matrix...)

Happy New Year to all !

    K.B.
--
Karim Belabas, IMB (UMR 5251)  Tel: (+33) (0)5 40 00 26 17
Universite de Bordeaux         Fax: (+33) (0)5 40 00 21 23
351, cours de la Liberation    http://www.math.u-bordeaux.fr/~kbelabas/
F-33405 Talence (France)       http://pari.math.u-bordeaux.fr/  [PARI/GP]
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